Reverse Sublist

Sometimes you need to reverse only a portion of a list. Nodes from position $m$ to $n$.

The approach:

$1.$ Find the node before position $m$ (call it prev)

$2.$ Reverse the sublist from $m$ to $n$

$3.$ Reconnect: prev.next points to new sublist head, old sublist head points to node after $n$

# After finding prev and the sublist
# Reverse the sublist, track its new head and tail
# Reconnect
prev.next = newSublistHead
oldSublistHead.next = nodeAfterN

This combines traversal, reversal, and careful pointer management. Practice until it becomes natural.